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Water Summary Update: the last year has been wetter, warmer

  • 10/18/2018 1:42:00 PM
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DES MOINES — The last year has been overall wetter and a bit warmer, according to the latest Water Summary Update.

Oct. 1 through Sept. 30 is known as the "water year," as snow accumulation after Oct. 1 serves as the primary source of runoff to streams during the following calendar year in many parts of the country. The 2018 Water Year (ending Sept. 30, 2018) brought a statewide precipitation average of 42.38 inches, or 7.11 inches more than normal, while temperatures averaged 48.1 degrees, about average.

This places 2018 as the sixth wettest and 45th warmest water year among 145 years of records.

Regionally, however, it was not wet across all of the state. Southern Iowa saw very dry conditions for much of the summer, with fall rains finally improving drought conditions. The resulting shallow groundwater conditions have improved across the entire state.

At least once in the 2018 WY, 87 U.S. Geological Survey stream gauges exceeded the National Weather Service flood stage. Record streamflows were recorded at several locations including on the Little Sioux and Floyd Rivers and Fourmile Creek.

For a thorough review of Iowa’s water resource trends, go to

The report is prepared by technical staff from Iowa DNR, the Iowa Department of Agriculture and Land Stewardship, IIHR—Hydroscience and Engineering, and the U.S. Geological Survey, in collaboration with Iowa Homeland Security and Emergency Management Department.